Research ArticleEffect of Anchote (Coccinia abyssinica) and Potato StarchAddition on Colloidal Stability of Pineapple Juice

Abebaw Teshome Tiruneh , Abebaw Ayele Negatu , and Neela Satheesh

Faculty of Chemical and Food Engineering, Bahir Dar Institute of Technology, Bahir Dar University, P. O. Box 26, Ethiopia

Correspondence should be addressed to Abebaw Teshome Tiruneh; abetsh01@gmail.com

Received 20 November 2020; Revised 4 March 2021; Accepted 15 April 2021; Published 4 May 2021

Academic Editor: Ahmed Al-Alawi

Copyright © 2021 Abebaw Teshome Tiruneh et al. This is an open access article distributed under the Creative CommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original workis properly cited.

Starch is one of the most important value-added food ingredients used as a thickener in many foods and industrial applications.This research investigated the effect of different concentrations of starch (anchote and potato) addition on the colloidal stabilityof pineapple juice. The experiment was carried out on a two-factor factorial design arranged in CRD. The first factor (starchtype with two levels (anchote and potato)) and the second factor (starch concentration with three levels (1%, 3%, and 5%)) wereconsidered. The starch-added juice samples were preserved for 15 days at room temperature. The physicochemical properties,colloidal stability, microbial counts, and sensory analysis were conducted in a 7-day interval including the first day. The resultsrevealed that different starch concentrations showed a significant effect (P ≤ 0:05) on the cloud stability, most of thephysicochemical properties and microbial count of pineapple juice as compared to the control. The turbidity and viscosity of thejuice samples were increased significantly (P ≤ 0:05) by the starch addition; in contrast, pulp sedimentation and microbialcounts were decreased. As storage duration increased, turbidity, viscosity, TSS, pH, and vitamin C content of juice decreased,whereas sedimentation, TA, and microbial count increased. The results revealed that the total bacterial and fungal counts ofpineapple juice samples were rising as storage durations increased. The maximum cloud retention was observed in juice addedwith 5% anchote starch. Finally, it is confirmed that starch (anchote and potato) addition positively affected the colloidalstability of pineapple juice and also possessed high potential to extend the shelf life.

1. Introduction

Pineapple (Ananas comosus (L.) Merr.) is the most versatile,commercially important, nonclimacteric tropical fruit thatbelongs to the Bromeliaceae family [1–3]. Pineapple fruit is arich source of sugars, fiber, organic acids, minerals (calcium,iron, and potassium), and vitamins (A, B, and C). Half a cupof pineapple juice provides 50% of an adult’s daily recom-mended amount of vitamin C [4]. Pineapple contains brome-lain, a proteolytic enzyme, which is highly useful in proteindegradation [2]. Due to the good flavor, aroma, juiciness, andsweetness, pineapple fruits are well known and appreciated byconsumers throughout the world. In addition, pineapple is alsoa rich source of health-promoting antioxidants, such as ascor-bic acid, flavonoids, and other phenolic compounds; hence, itis attracting both the consumer and processor [2, 5–7]. Pineap-

ple fruits are widely consumed in fresh or as the processed juiceamong all the age groups. Pineapple juice is classified as a non-alcoholic beverage, and the demand is rising constantly due tothe consumer awareness on its health benefits [8, 9].

Pineapple is a seasonal fruit crop and perishable innature, and due to the presence of high sugar and moisturecontents, postharvest losses during peak harvesting seasonsare considerably high (40%) [2, 3]. Hence, alternative pro-cessing and preservation methods are very important [10].Pineapples can preserve for a short duration in cold storagefurther, processed into shelf-stable value-added products(juice, desserts, squash, jam, jelly, and canned pineappleslices) to reduce postharvest losses [6, 11]. Pineapple juiceis an unstable suspension that settles quickly after extraction,and such phase separation depreciates the visual appearanceof the product [11].

HindawiInternational Journal of Food ScienceVolume 2021, Article ID 6615273, 12 pageshttps://doi.org/10.1155/2021/6615273

A small percentage of insoluble particles (mixture of pro-teins, pectins, lipids, hemicellulose, cellulose, and other minorcomponents) remain in the cloudy juice processing. Achievingthe bright, natural color is not possible in cloudy fruit juices[12–14]. In addition, cloud loss in juices is an objectionablescenario to the consumers. Presence of insoluble matter inclear beverages is considered as an indication of spoilage. Onthe other hand, colloidal suspensions in fruit juices are pre-ferred, as cloud imparts characteristic flavor, color, and mouthfeel. Therefore, it is important to maintain and improve juiceturbidity to meet consumer demands [14, 15].

Hydrocolloids are used widely in fruits, vegetables, andprotein-based juices to improve color or cloud stability for pro-longed periods due to their thickening (raising the viscosity)and suspension properties [11, 14–17]. Starch is increasinglyused as a functional ingredient in industrial applications andfood processing due to its ability as a thickening agent [18].

Hence, using starch as a stabilizer in fruit juice proves to bevigorous due to its effectiveness, availability, and low in cost.On the other hand, starch does not alter the organolepticand sensory properties of the juice compared to other hydro-colloids. Researchers reported the use of carboxymethyl cellu-lose (CMC), low-methoxyl pectin, guar, xanthan, and gellangum, [16, 19], sodium alginate, [14], and guar gum [15, 17,20] in carrot, orange, mulberry, and apple juices. Starch iswidely used in yogurt preparation as a thickener to reducedefects, making the body and texture of manufactured yogurtappealing as well as reducing cracks in the surface of the curdmilk [18, 21]. However, studies on starch addition in fruit juicefor colloidal stability are relatively limited. So, in this study, weused different concentrations of the starch from potato andanchote as the stabilizer in pineapple juice.

Anchote (Coccinia abyssinica) is an indigenous roottuber crop widely produced in southern and southwesternparts of Ethiopia. Anchote is a drought tolerant crop provid-ing food security; it is a highly productive and nutritionallyample crop [22]. Nutritionally, anchote is a good source ofcarbohydrates, proteins, minerals, and fiber [22, 23]. Potatois also an important ingredient for nutrition due to the goodsource of starch, vitamins A and C, and minerals such as ironand potassium and fiber [18].

The objective of this research is to determine the effect ofpotato and anchote starch at 1%, 3%, and 5% on the physio-chemical properties, microbial growth, and stability of pineap-ple juice during short storage durations at room temperatures.

2. Materials and Methods

2.1. Procurement of the Ingredients. Fully ripened pineapple(Cayenne cultivar) was purchased from the local market ofthe Bahir Dar City. Anchote (Coccinia abyssinica) tuberwas collected from the local market of Nekemte Town,Oromia Region, Ethiopia. Commercial potato starch waspurchased from the local market of Bahir Dar City, Ethiopia.

2.2. Starch Extraction from Anchote. As the anchote starchwas not readily available, isolation and purification weredone by Sit et al. [24] method. The raw anchote tuber waswashed and was peeled and chopped using a mechanical

blender for 4min (EP 5, vertical cutter-mixer, France). A10% (w/v) crushed tuber mass and water suspension wereprepared. The suspension was filtered through 250μm sieves,and the filtrate was allowed to settle for 12h. The supernatantwas decanted, and the sediment was washed until the purewhite in color is obtained. The resulting starch was finally driedat room temperature, milled to fine powder in a mortar andpestle, sieved through 224μm mesh, and stored in an airtightplastic container under dry conditions for further use [22].

2.3. Experimental Design. The experiment was set as 2 × 3factorial design arranged in CRD. The first factor consideredstarch type with two levels (potato and anchote). The secondfactor is starch concentration in three levels (1, 3, and 5%),and each treatment was conducted in triplicate and totalexperimental runs conducted in this experiment were 18and pineapple juice without any starch addition was consid-ered as control.

2.4. Preparation of Pineapple Juice. The fully ripened pineap-ple fruits were washed thoroughly with potable water toremove dirt. The cleaned pineapples were peeled off andcut into pieces with sterile stainless steel kitchen knife. Then,the pineapple pieces were homogenized in a clean electriclaboratory disperser (SWFS1.1-00, China). The pineapplejuice was filtered through 500μm aperture stainless steelsieve screen into a clean transparent plastic bowl [7, 25].Then, commercial potato and anchote starches were addedto the pineapple juice at concentration levels of 1%, 3%,and 5% (w/v) as a designed experiment. The juice was mixedby a magnetic stirrer until complete dissolution of the starch.After incorporation of the starch, pineapple juices were bot-tled and allowed for storage studies at room temperature(28°C ± 2°C) for fifteen (15) days. The stability of color andcloud was measured at every 7-day interval for 15 days.

2.5. Determination of Physicochemical and FunctionalProperties of Starch

2.5.1. Bulk Density. Bulk density of starch samples was deter-mined according to the method of Ohizua et al. [26]. Starchsample (50 g) was taken into a 100ml measuring cylinder.The cylinder was tapped several times on a laboratory benchto a constant volume. Bulk density (g/cm3) was calculated bydividing the weight of sample on its volume after tapping.

2.5.2. Water Absorption Capacity (WAC). The WAC of thestarch samples was determined by the method of Bello-Pérezet al. [27]. One gram of flour sample was mixed with 10ml ofdistilled water and allowed to stand at ambient temperature(30 ± 2°C) for 30 min, and then centrifuged (L-530 tabletoplow-speed centrifuge, China) for 30min at 3000 rpm. The clearsupernatant was decanted. Water absorption was expressed aspercent water bound per gram flour.

2.5.3. Swelling Power (SP) and Water Solubility Index (WSI).Swelling power and WSI were determined according to themethod described by Bello-Pérez et al. [27]. 0.5 g of the starchsample was taken in a preweighed centrifuge tube. About10ml of distilled water was added and mixed gently. The

2 International Journal of Food Science

tubes were heated in a thermostatic water bath at 20, 50, 65,75, and 85°C for 30min by shaking every 5min interval andthen cooled to room temperature. The suspensions werecentrifuged for 15min at 2000 rpm. The supernatants weredecanted immediately after centrifugation to preweighedPetri dishes and dried in an oven for 2 h at 120°C. The resi-dues obtained after drying of the supernatant represent theamount of starch solubilized in water. The solubility wascalculated as gram per 100 g of sample on a dry weight basis.The sediment obtained was weighed to determine the swell-ing of the starch. The swelling power and water solubilityindex were determined according to the following equations:

Swelling power = Weight of swollen granules × 100Weight of sample −Weight of dissolved starch ,

ð1Þ

Solubility index %ð Þ = Weight of dried starch in Petri dish × 100Sample weight :

ð2Þ2.6. Determination of Proximate Composition of Potato andAnchote Starch. The moisture content, ash, crude protein,and fat contents were determined according to the AOAC(2006) method numbers 950.46, 920.153, 992.15, and989.05, respectively. The total starch content was determinedby the AOAC (2007) method number 996.11 [22].

2.7. Determination of Amylose and Amylopectin Content ofPotato and Anchote Starch. Amylose and amylopectin con-tents were determined by using the method of Hassan andHassan [28] as cited by Williams et al. [29]. Briefly, 0.10 gof the sample was weighed into a 100ml volumetric flaskand 1ml of 99% ethanol and 9ml of 1M sodium hydroxidesolution was added. The contents were mixed thoroughlyand heated for 10min in boiling water (100°C) to gelatinizethe starch. After cooling, the solution was made up to thecalibration mark with distilled water and shaken thoroughly.5ml of prepared starch solution was taken into a 100mlvolumetric flask and was treated with 1ml of 1M acetic acidand 2ml of iodine solution. The solution was diluted to thecalibration mark with distilled water, and the absorbancewas determined by a spectrophotometer at 620 nm. Amyloseand amylopectin contents were calculated using the follow-ing equations.

Amylose content %ð Þ = 3:06 × absorbance × 20, ð3Þ

Amylopectin %ð Þ = 100 −%amylose content: ð4Þ2.8. Determination of Physicochemical Properties ofPineapple Juice

2.8.1. Total Soluble Solids. Total soluble solid (TSS) content ofpineapple juice was measured using a hand refractometer(RX-5000i-Plus, Atago, Tokyo, Japan) (AOAC 2000). 1mlof a well-homogenized pineapple juice was placed on theprism of a calibrated hand refractometer. The readings weretaken, and results were expressed in °Brix.

2.8.2. pH and Titratable Acidity. pH of starch and pineapplejuice was determined by using a calibrated pH meter withstandard solution of pH 4 and 7. Each sample (10ml) wastaken into a beaker, and then, electrodes of the pH meter(PHS-25/3C, China) were immersed into the sample andthe readings were recorded directly (AOAC, 2004).

The titratable acidity (TA) was determined according toAOAC (2004) procedure. 10ml of sample was taken into aconical flask, and three drops of phenolphthalein indicatorwere added. The mixture was titrated against 0.1N NaOHsolution. The TA was calculated by the standard formula byusing a citric acid titer value and expressed as the citric acid[30].

2.8.3. Viscosity. Dynamic viscosity of starch and pineapplejuice was determined in an Ostwald viscometer (VISCOSTAR+H, Spain) at 20°C and expressed in mPa s [14, 31].

2.8.4. Turbidity. The stability of pineapple juice was assessedby serum cloudiness (turbidity). Cloud stability of the centri-fuged samples (4000 rpm for 15min) (expressed in terms of% light transmission) was determined by measuring absor-bance at 660nm using a UV-Vis spectrophotometer (AgilentCary 60 UV-Vis spectrophotometer, USA) calibrated withdistilled water. The absorbance at 660nm was directly relatedto the turbidity of pineapple juice and expressed in nephelo-metric turbidity units [11, 15, 16].

2.8.5. Sedimentation Measurement. The pulp sedimentationof pineapple juice was determined according to the methodof Silva et al. [11]. The pineapple juice sample was transferredinto a graduated 100ml cylinder and stored at 25°C for 24h(early evaluation) and for a total of 15 days (simulating ashelf life evaluation). The volume of sediment was measured(total volume minus the serum phase), and the sedimenta-tion index was calculated as follows:

IS = V infV total

, ð5Þ

where V inf is the sediment volume (ml) and V total is the totalvolume of the sample (ml).

2.9. Vitamin C Content. Vitamin C content was determinedby an iodometric titration method as described by Nwezeet al. [32].

2.10. Sensory Acceptability. Sensory acceptability of pineapplejuice was conducted by untrained 20 volunteer panelists (8females and 12 males) in a hedonic test. The coded pineapplejuice samples were presented to panelists randomly for like-ness scores on sensory evaluation (taste, flavor, color, consis-tency, aroma, texture, mouth feel, and overall acceptability)by using a seven-point hedonic rating scale where 7 representslike extremely and 1 represents dislike extremely [1, 33].

2.11. Shelf Life Determination of the Pineapple Juice. Thepineapple juices with different starch levels were stored atambient temperature for fifteen (15) days. The shelf life of

3International Journal of Food Science

the juice was determined by checking the pH weekly and bydetermining the microbial growth [9].

2.11.1. Microbiological Analysis of Pineapple Juices. Enumer-ations of aerobic plate count (APC) and total fungal countswere performed according to the ISO standard method(ISO-4833:2003(E)). Enumeration of APC was done by theserial dilution technique followed by a pour plate method.

At the initial day, 7th day, and 15th day, serial dilution wascarried out by taking pineapple juice from each bottle. Theserially diluted juice sample (0.1ml) with dilution factor 103

for fungal enumeration and 104 for bacterial enumerationwas plated and incubated at 37°C for 24 h for bacteria andfor fungi at room temperature for 72h. The colonies frombacteria were counted using the colony counter. The meanvalue of the triplicate was taken, and the number of colonieswas multiplied by the dilution factor and calculated as 1ml oforiginal sample. It was then expressed as colony-forming unitper ml (cfu/ml) of the sample [9].

2.12. Statistical Data Analysis. A triplicate data was subjectedto analysis of variance (ANOVA) using Minitab version 19.2.Analysis of variance was performed with the general linearmodel. The mean separation was done by the Tukey methodand considered a significant difference at P ≤ 0:05. Theresults were presented as the mean ± standard deviation.

3. Results and Discussions

3.1. Physicochemical and Functional Properties of Starch. Theresults on physicochemical and functional properties of thepotato and anchote starches are given in Table 1. Previousstudies report that blends of starches have been used as thick-ening agents and stabilizers to control water mobility, facilitateprocessing, and improve stability in food systems [18, 34].

A significant difference (P ≤ 0:05) was observed in thefunctional properties of potato and anchote starch except inbulk density and pH. The bulk densities of potato andanchote starches were observed as 1.5 g/ml and 1.4 g/ml,respectively. The bulk density is affected by the particle sizeand the density of the starch flour. This functional propertyis very important in determining the packaging require-ments, material handling, and the compatibility in wet pro-cessing in food industry [35]. The higher bulk density ofstarch suggests their suitability for use in food preparations.In contrast, low bulk density would be an advantage in theformulation of complementary foods [36]. The present studyrevealed that bulk density of starches was observed higher; itindicates that starch would serve as better thickeners in foodproducts.

The mean WAC of 1.4 g/g and 1.1 g/g was observed forpotato and anchote starch, respectively. The highest WACof potato starch could be attributed to the presence of higheramount of carbohydrates (starch) and fiber. The fibers havegood ability to associate with water under limited water pres-ence (high hydration properties) [35]. TheWAC is the abilityof the starch to hold water against gravity. Presence ofproteins and carbohydrates enhances the WAC of starch byproviding hydrophilic groups like polar and charged side

chains. Water plays an important role in food quality and sta-bility. TheWAC is desirable in different foods to imbibe waterwithout dissolution of protein, thereby attaining body thicken-ing and viscosity [37]. High water holding capacity will rise tohigh swelling power and high peak viscosity. Root and tuberstarches with high level of WAC are useful in meeting theneeds for starch incorporation into juice production [38].

The SP showed 4.9% for potato starch, whereas 6.2% foranchote starch. The capacity to hydrate and swelling allowschanges in starch viscosity. The higher amylopectin contentis responsible for higher SP and viscosity at low temperatures.The swelling capacity of starch granules allows increasing theirviscosity and gelling properties [39]. The differences in SP ofthe two starches may be ascribed to variations in amyloseand nonstarch contents. The swelling power showed weaknegative correlation with amylose content. This suggests thathigher swelling starches had lower amylose and protein con-tents [40].

The WSI values of the starches were 1.2 g/g and 0.6 g/gfor potato and anchote, respectively. WSI measures the num-ber of free molecules leached out from the starch granules inaddition to excess water and thus reflects the extent of starchdegradation [41].

The mean viscosity values were observed as 235.3mPa sand 241.7mPa s for potato and anchote starches, respec-tively. The higher viscosity was observed for the anchotestarch. The results of pH for starch samples were reportedas 6.0 and 6.1 for potato and anchote starch, respectively.The pH values of the starch in water suspension are impor-tant because some functional properties like solubility andemulsion properties are highly affected by change in pH[37]. The minimum solubility for most of the starches wasobserved at pH 4.0 and 6.0. The high solubility of starchesunder highly acidic conditions (pH 2.0) may be due to theirenhanced hydrophilic character and partial hydrolysis.Under alkaline conditions, the starch may undergo to partialgelatinization, thus resulting starch results in higher solubil-ity at pH 10.0 [23]. In general, both potato and anchotestarches can be used to enhance viscosity and thicken, stabi-lize, and enhance the mouth feel and smoothness of foods.

3.2. Proximate Composition of Starch. Analysis of varianceshowed significant difference (P ≤ 0:05) among potato andanchote starches in the proximate composition (Table 2)with the exception of crude protein and fat content. Themoisture contents of the potato and anchote starches wereobserved as 5.3% and 10.3%, respectively, which were withinthe safe limit for storage requirements for starches [42]. Theanchote starch had the higher moisture content than thepotato starch and this may be attributed to the variation inmethods used for the starch extraction. These results arehigher than previously reported by Abera et al. [22]. Therecommended moisture content for storing commercialstarch is 10–12%. The moisture content > 12% encouragesthe microbial growth and induces degradative biochemicalreactions leading to spoilage of starches in storage [40].Starches with lower moisture content are less prone to micro-organism degradation, making amenable for utilization inindustries like the pharmaceutical industry. Moisture

4 International Journal of Food Science

contents lower than 10% are required for starch incorpora-tion into low-density polyethylene matrix in the productionof biodegradable products [28, 36].

The crude protein contents of potato and anchotestarches were 0.30% and 0.4%, respectively. The protein con-tents of starches were similar as previously reported by Aberaet al. [22]. Low protein content is may be due to the sources,usually, roots and tubers that do not contain endospermprotein which could affect the purity and crystal structureof the starches. Low protein content of the starches adverselyaffects the physicochemical properties of the starches [28].The fat contents in starches were observed as 0.2% and0.30% for potato and anchote, respectively. These values werein agreement with the report of Parmar et al. [43] and Aberaet al. [22]. The ash contents were observed as 0.3% and 1.1%for potato and anchote starch, respectively. Earlier studiesreported ash contents similar with the present study resultsof potato and anchote starches [22, 43, 44]. The low ash con-tent is a quality indicator for a good quality starch [28]. Theash content below 0.5% is recommended for higher-gradeindustrial starches [45].

3.3. Amylose and Amylopectin Contents of Potato andAnchote Starch. The total starch contents in potato andanchote starches were observed as 89.7% and 76.3%, respec-tively. The value of potato starch content was similar with thevalue reported by Abera et al. [22]; in contrast, a lower valuewas recorded for anchote starch contents.

The amylose contents in potato and anchote starcheswere 25.7% and 15.8%, respectively. Similar amylose contentin potato starch has been reported by Sanchez-González et al.[31] and Vafina et al. [46]. The amylose content of starchdetermines its properties (such as water binding capacity,thickening, and gelling) and dictates most of its end uses.With the determined amylase contents, both the starchescan successfully applied in industries as thickeners andbinders [28]. High amylose content starch granules had lowlipid and ash contents. Lipids bind to amylose molecules leadto the formation of an amylose-lipid complex that competeswith iodine to form a complex [40, 47].

The amylopectin contents in potato and anchote starcheswere 75.8% and 84.5%, respectively. Similar amylose contentin potato starch has been reported by Sanchez-González et al.[31]. The relative amounts of amylose and amylopectin areknown to influence both nutritional and technological prop-erties of starch such as susceptibility to enzymatic hydrolysis,gelling, and pasting behavior, which could be of biotechno-logical importance [48].

3.4. Effect of Starch Addition on Physicochemical Properties ofPineapple Juice. The results on the physicochemical proper-ties of pineapple juice as a function of storage time are givenin Table 3. It can be observed that the effect of all main factorsand their interactions was significantly affected on sedimen-tation of juice at P ≤ 0:05. There was a significant differenceobserved due the effect of starch type and concentration onsedimentation of pineapple juice after 7 days of storage.The results showed that the highest sedimentation wasobserved in control samples (51.33%) stored for 15 days,whereas no (0%) sedimentation was observed on the initialday of storage. In terms of starch type, the highest sedimenta-tion (31.17%) was observed in 5% potato starch-added sam-ples while the lowest sedimentation (6.50%) was observed in5% anchote starch-added pineapple juice samples stored for15 and 7 days, respectively.

Pineapple juices with potato starch showed highersedimentation than juice with anchote starch. The controlsamples showed highest degree of sedimentation as com-pared to starch-added samples during the storage time. Thesedimentation and phase separation were observed in thefirst 24 h of stored control samples; it is a common behaviorof some fruit juices [11]. After the first day of storage, bothstarch-added and control samples showed particle sedimen-tation as an increase in storage durations. The majorsedimentation changes were happened in the first 7 days ofthe storage. Moreover, it is interesting to note that the controlsamples showed quicker sedimentation than the starch-added samples. This may be due to the aggregation of parti-cles, which causes quick sedimentation.

Table 1: Functional and physicochemical properties of potato and anchote starch.

Starch sample Bulk density (g/cm3) WAC (g/g) WSI (g/g) Swelling power (%) Viscosity (mPa s) pH

Anchote 1:4 ± 0:1A 1:1 ± 0:2A 0:6 ± 0:1A 5:5 ± 0:2A 241:7 ± 1:5A 3:3 ± 0:2A

Potato 1:5 ± 0:1A 1:4 ± 0:2B 1:2 ± 0:2B 4:9 ± 0:1B 235:3 ± 1:5B 3:4 ± 0:1A

P value ≤0:124 ≤0:026 ≤0:005 ≤0:001 ≤0:007 ≤0:152Values are presented as the means ± standard deviations (n = 3). Means with different superscript letters within a column differ significantly, P ≤ 0:05. WAC:water absorption capacity; WSI: water solubility index.

Table 2: Proximate composition and amylase and amylopectin contents of starch from anchote and potato tubers.

Starch sample Moisture (%) Ash (%) Fat (%) Starch (%) Protein (%) Amylose (%) Amylopectin (%)

Anchote 10:3 ± 0:6A 1:1 ± 0:1A 0:3 ± 0:1A 76:3 ± 0:6A 0:4 ± 0:1A 15:8 ± 0:8A 84:5 ± 0:5A

Potato 5:3 ± 0:6B 0:3 ± 0:1B 0:2 ± 0:1A 89:7 ± 0:6B 0:3 ± 0:1A 25:7 ± 0:6B 75:8 ± 0:8B

P value ≤0:001 ≤0:001 ≤0:206 ≤0:001 ≤0:116 ≤0:001 ≤0:001Values are presented as the means ± standard deviations (n = 3). Means with different superscript letters within a column differ significantly at P ≤ 0:05.

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Table 3: Physicochemical properties of pineapple juice samples added with different types of starch with different concentrations stored for15 days.

Storage time (days)Juicesample

Sedimentation(%)

TSS (%) pHViscosity(mPa s)

Turbidity(FTU)

TA (%)Vitamin C(mg/100g)

Initial day

Control —14:30 ± 0:78

AB3:47 ± 0:11

A 24:0 ± 1:0F 432:67 ± 1:15G

0:28 ± 0:02AB 21:57 ± 0:50A

AS1 —14:39 ± 0:43

AB3:49 ± 0:28

A39:33 ± 1:53

D481:33 ± 0:58

E0:27 ± 0:02

AB 21:25 ± 0:45A

AS3 —14:52 ± 0:66

AB3:46 ± 0:12

A60:33 ± 1:53

B555:33 ± 1:15

C0:26 ± 0:01

B 21:23 ± 0:08A

AS5 —15:13 ± 0:57

A3:44 ± 0:06

A 70:0 ± 1:0A 696:33 ± 2:08A

0:25 ± 0:01B 21:50 ± 0:36A

PS1 —14:34 ± 0:62

AB3:42 ± 0:06

A33:33 ± 1:15

E462:67 ± 1:15

F0:27 ± 0:01

AB 21:48 ± 0:18A

PS3 —14:36 ± 0:44

AB3:43 ± 0:05

A49:33 ± 0:58

C496:67 ± 0:58

D0:27 ± 0:01

AB 21:53 ± 0:45A

PS5 —14:87 ± 0:70

A3:40 ± 0:07

A59:67 ± 1:53

B569:67 ± 1:53

B0:26 ± 0:02

B 21:64 ± 0:67A

Day 7

Control 31:0 ± 1:0A 14:22 ± 0:29A

3:22 ± 0:13A

19:33 ± 1:15F

225:33 ± 1:53FG

0:32 ± 0:01C 20:47 ± 0:37A

AS1 16:83 ± 0:76C 14:32 ± 0:24A

3:20 ± 0:10A

30:67 ± 1:15E

271:67 ± 1:53D

0:33 ± 0:02BC 20:23 ± 0:24A

AS3 12:33 ± 0:58D 14:45 ± 0:19A

3:21 ± 0:14A 43:0 ± 1:0C 406:33 ± 1:53

C0:34 ± 0:01

ABC 20:78 ± 0:48A

AS5 6:50 ± 0:50F 15:01 ± 0:55A

3:20 ± 0:20A

67:67:0 ± 58A

595:33 ± 1:53A

0:36 ± 0:02AB 20:87 ± 0:76A

PS1 20:83 ± 1:26B 14:30 ± 0:19A

3:24 ± 0:17A 29:0 ± 1:73E 222:67 ± 1:53

G0:35 ± 0:02

ABC 20:11 ± 0:12A

PS3 14:0 ± 1:0D 14:34 ± 0:31A

3:16 ± 0:07A 40:0 ± 1:0D 238:0 ± 1:0E 0:36 ± 0:02

ABC 20:17 ± 0:19A

PS5 9:50 ± 0:87E 14:68 ± 0:81A

3:19 ± 0:12A

64:67 ± 1:53B

424:67 ± 1:15B

0:38 ± 0:01A 20:47 ± 0:20A

Day 15

Control 51:33 ± 0:58A 13:15 ± 0:06A

2:02 ± 0:04A 10:0 ± 1:0G 102:0 ± 1:0G 0:49 ± 0:01

BC 17:77 ± 0:08A

AS1 18:50 ± 0:50E 13:43 ± 0:34A

2:03 ± 0:06A 25:0 ± 1:0E 172:33 ± 2:08

E0:47 ± 0:02

C 17:35 ± 0:35A

AS3 22:0 ± 1:0CD 13:75 ± 0:66A

2:08 ± 0:10A

35:33 ± 0:58C

226:33 ± 2:31C

0:51 ± 0:01ABC 17:40 ± 0:26A

AS5 29:83 ± 0:76B 13:97 ± 0:55A

2:04 ± 0:05A

64:33 ± 1:53A

377:33 ± 1:53A

0:50 ± 0:01ABC 17:63 ± 0:28A

PS1 20:17 ± 1:04DE 13:03 ± 0:57A

2:03 ± 0:04A 19:0 ± 1:0F 152:33 ± 2:08

F0:48 ± 0:01

ABC 17:30 ± 0:17A

PS3 24:0 ± 1:0C 13:23 ± 0:40A

2:02 ± 0:02A 32:0 ± 1:0D 206:0 ± 2:65

D0:52 ± 0:03

A 17:80 ± 0:56A

PS5 31:17 ± 0:76B 13:69 ± 0:88A

2:00 ± 0:01A 55:0 ± 1:0B 349:03 ± 0:15

B0:51 ± 0:02

AB 17:85 ± 0:18A

P value

Starch type ∗ concentrationInitialday

— ≤0:185 ≤0:54 ≤0:001 ≤0:001 ≤0:098 ≤0:032Starch type — ≤0:262 ≤0:229 ≤0:001 ≤0:001 ≤0:065 ≤0:26Starch concentration ≤0:003 ≤0:148 ≤0:001 ≤0:001 ≤0:009 ≤0:457

Starch type ∗ concentrationDay 7

≤0:001 ≤0:962 ≤0:314 ≤0:001 ≤0:001 ≤0:052 ≤0:686Starch type ≤0:001 ≤0:125 ≤0:885 ≤0:001 ≤0:001 ≤0:001 ≤0:074Starch concentration ≤0:001 ≤0:012 ≤0:177 ≤0:001 ≤0:001 ≤0:21 ≤0:005

6 International Journal of Food Science

As the storage time increased, the sedimentation alsoincreased; in contrast, as the starch concentration increased,the sedimentation decreased in the first 7 days of storagewhile increased after 7 days of storage. This may be due tothe increase in concentration of starch that leads to the settle-ment of cloud. It has been reported that incorporation ofstarch with higher concentrations leads to a higher electrolyteconcentration, resulting in salting out of the starch [14].Pineapple juice with anchote starch was showing less sedi-mentation than pineapple juice with potato starch.

The sedimentation decreased significantly (P ≤ 0:05)with increasing levels of starch incorporation into the pine-apple juice as compared with the control samples. This maybe attributed to the rise in the juice viscosity due to theaddition of the starch. In general, the sedimentation of juicesvaried significantly (P ≤ 0:05) with increasing levels of starchaddition and storage durations. As given by the Stokes law,particle sedimentation velocity is inversely proportional tothe dispersed medium viscosity [11, 49]. Therefore, theincrease in viscosity prevents aggregation of particles thatcauses a reduction in particle size in the suspension. Thiscan be attributed to the greater stability of the starch-addedsamples, and starch can be seen as an important tool in pre-venting the juice sedimentation.

Analysis of variance (Table 3) showed that the effect ofinteractions and main effects was not significant on pH ofpineapple juice at P ≤ 0:05. There was no significantdifference (P ≤ 0:05) that was observed due to the effect ofstarch type and concentration on pH of pineapple juice as afunction of storage durations. As the results have showed,the highest pH (3.49) value was observed in 1% anchotestarch-added juice at the initial day, while the lowest (2.0)was determined in 5% potato starch-added pineapple juiceafter 15 days of storage. Besides, depending on the starch type,the highest pH was shown in 1% anchote starch-addedsamples, while the lowest was observed in 5% potato starch-incorporated juice (Table 3). Pineapple juices added withpotato starch have shown higher pH than juice with anchotestarch. The statistical analysis implied that as the storage timeincreases, the pH level in pineapple juice was considerablydecreased due to the production of organic acids duringstorage because of fermentation. However, pH remainedalmost unchanged with the increasing level of starch and typeof starch. Mahomud et al. [50] reported an increase in pH oftomato juice with the addition of starch which was deviatedfrom the findings of this work. The pH results observed in this

study were similar to the value reported by Nadzirah et al.[10]. In general, incorporating the starch had no significanteffect on the mean value of the pH of pineapple juice.

The effect of interactions and main effects was significant(P ≤ 0:05) in TA of pineapple juice as illustrated in Table 3. Asignificant difference in TA was observed by the effect ofstarch type. However, there was no significant effect observed(P ≤ 0:05) due to starch concentration on TA of pineapplejuice except on the 7th day of storage in both the starch typeadditions. The highest TA (0.52%) was observed in 3% potatostarch-added pineapple juice samples after 15th days ofstorage. In contrast, the lowest TA (0.25%) is in 5% anchotestarch-added pineapple juice samples at the initial day. Interms of starch type, the highest TA was observed in 3%potato starch, whereas the lowest is in 5% anchote starch-added pineapple juice. The juices with potato starch showedslightly higher TA than anchote starch-added juices. How-ever, it remained almost unchanged with the increasing con-centration of starch.

The ANOVA showed that pineapple juices exhibited aslight increase in the TA over storage time and were signifi-cantly varied (P ≤ 0:05). The TA results of this study were inagreement with reports of Ghafari and Ansari [33] and Sham-sudin et al. [3]; they reported a significant relationshipbetween the gradual increase in acidity of pineapple juiceduring the storage and the amount of organic acid produced.In this study, generally, the results of TA increased as the stor-age duration increased, but it remained almost unchangedwith starch type and increasing levels of starch concentration.

The ANOVA showed that the effect of interactions wasnot significant on TSS of pineapple juice at P ≤ 0:05. Besides,there was no significant effect (P ≤ 0:05) on TSS due to starchtype except on the 15th day of pineapple juice has stored. Therewas a significant effect (P ≤ 0:05) on TSS of pineapple juiceduring storage by starch concentration except the 15th day ofstorage. The results showed that the highest TSS was observedin 5% anchote starch (15.13%) at the initial day, while the low-est TSS (13.03%) was observed in 1% potato starch-addedpineapple juice after the 15th day of storage. In addition, interms of starch type, the highest TSS was observed in thesamples with 5% anchote starch addition, while the lowestwas observed in 1% potato starch-incorporated juice. Pineap-ple juices with anchote starch showed a slightly higher TSSthan juice with potato starch addition. However, there wasno statistically significant difference; a slight increase in TSSwas observed as starch concentration increased.

Table 3: Continued.

Storage time (days)Juicesample

Sedimentation(%)

TSS (%) pHViscosity(mPa s)

Turbidity(FTU)

TA (%)Vitamin C(mg/100g)

Starch type∗ concentration

Day 15

≤0:001 ≤0:839 ≤0:54 ≤0:001 ≤0:001 ≤0:034 ≤0:216Starch type ≤0:001 ≤0:06 ≤0:229 ≤0:001 ≤0:001 ≤0:053 ≤0:072Starch concentration ≤0:001 ≤0:198 ≤0:148 ≤0:001 ≤0:001 ≤0:006 ≤0:18Values are presented as the means ± standard deviations (n = 3). Means with different superscript letters within a column differ significantly at P < 0:05.Control: pineapple juice without starch; AS1: 1% anchote starch; AS3: 3% anchote starch; AS5: 5% anchote starch; PS1: 1% potato starch; PS3: 3% potatostarch; PS5: 5% potato starch.

7International Journal of Food Science

The analysis of variance revealed that TSS of pineapplejuices slightly decreased over storage durations and werenot significantly varied (P ≤ 0:05) between the treatments.At lower pH, juices are comparatively effluent in organicacids and result in low TSS content [51]. Besides, significantdifferences (P ≤ 0:05) were not observed on TSS by starchtype and starch concentration. The results of TSS are similarto the values reported by Lu et al. [5], Ghafari and Ansari[33], and Shamsudin et al. [3].

There was no significant (P ≤ 0:05) difference observeddue to the interactions effects on vitamin C content of pine-apple juice, except at the initial day of storage. A significantdifference (P ≤ 0:05) was not observed in vitamin C contentof pineapple juice by the effect of starch type and starch con-centration, except a significant effect by starch concentrationwas observed at the 7th day of storage. The highest vitamin Cconcentration was observed in 5% potato starch-added juicesample (21.64mg/100g) at the initial day, whereas the lowestvitamin C content (17.30 mg/100g) was determined in 1%potato starch-added pineapple juice after 15 days of storage.Similar results were observed due to the starch type withrespect to the highest and lowest vitamin C content ofpineapple juice. The vitamin C content of pineapple juicewith potato and anchote starches was almost unchanged.The vitamin C content in starch-added and control pineap-ple juice samples was observed higher on initial day. Simi-larly, there was no significant statistical difference amongthe vitamin C composition of different samples on initialday. However, as the storage duration increases, the vitaminC content decreased in all the samples. This result was inagreement with reports of Rashima et al. [1], Hounhouiganet al. [52], and Wardy et al. [53]. The vitamin C content ofpineapple juice decreases gradually with increase in storagetime especially after 7 days of storage due to the oxidationreactions [30]. However, there was no significant difference(P ≤ 0:05) on vitamin C content. Besides, there was no differ-ence (P ≤ 0:05) observed in vitamin C content of pineapplejuice due to the starch concentration and type of starch.

The ANOVA showed that the viscosity of pineapple juicesignificantly (P ≤ 0:05) depends on interactions and maineffects. The results showed that the highest viscosity (70mPa s)was observed in 5% anchote starch-added pineapple juice atthe initial day, while the lowest viscosity (10mPa s) wasobserved in control juice after 15 days of storage. Moreover,in terms of starch type, the highest viscosity (70mPa s) wasshown in 5% anchote starch, whereas the lowest viscosity(19mPa s) was observed in 1% potato starch-incorporatedjuice. Juices with anchote starch were observed for higherviscosity than juice with potato starch addition. As the con-centration of the starch increased in the juice, the viscosity alsoincreased. Besides, as the storage time increased, the viscosityof pineapple juice decreased significantly (P ≤ 0:05).

This tread may be attributed to the degree of starchpolymerization. With a high degree of polymerization, thesolution viscosity will be high. The results of the presentstudy are in agreement with the findings of Shamsudinet al. [25]. Compared with starch type, anchote starch facili-tated more viscous juice than potato starch. Lower concen-tration of starch addition facilitated pineapple juice with

low viscosity, and as the storage duration increased, phaseseparation occurred in the product. This trend in this resultcorresponds to the theory of Tan [54]; increasing viscositycorresponds to the increase in the stability in turbidity [20].Generally, in this study, it is observed that storage time,starch concentration, and type of starch affected the viscosityof pineapple juice significantly (P ≤ 0:05).

The statistical analysis showed that the effect of interac-tions and main effects was significant on the turbidity of pine-apple juice at P ≤ 0:05. The results revealed that the highestturbidity (696.33FTU) was observed in 5% anchote starch-added pineapple juice at the initial day, while the lowest tur-bidity (102FTU) was observed in control juice after 15 daysof storage. Besides, in terms of starch type, the highest turbid-ity (696.33FTU) was observed in 5% anchote starch, whereasthe lowest turbidity (152.33FTU) was in 1% potato starch-incorporated juice. Pineapple juice with anchote starchshowed higher turbidity than juice with potato starch-addedsamples. As the concentration of the starch increased in thejuice, the turbidity increased significantly (P ≤ 0:05). More-over, as the storage duration increased, the turbidity of pineap-ple juice decreased significantly (P ≤ 0:05). The major changesin the turbidity of the pineapple juice were taken place in thefirst 7 days of the storage. As storage time increased, cloudi-ness decreased with rise in the starch concentration. Thiscan be attributed to the decrease in viscosity and increase inparticle sedimentation which allows more light to transferthrough the juice. The results of this study revealed that asthe increase in starch concentration is from 1% to 5%, thepineapple juice cloudiness also increased due to the loss inviscosity andmovement of particles in the system. The controljuice showed a lesser degree of cloudiness as compared to thestarch-added juice samples during the storage period.

The turbidity of the pineapple juice decreased signifi-cantly (P ≤ 0:05) with increase of storage duration as com-pared to the control samples. In addition, the turbidity ofjuices varied significantly (P ≤ 0:05) with increase of starchconcentration and starch type. Moreover, all the juice sam-ples showed cloudiness variation along the storage durations,reflecting the particle aggregation due to attractive forces.The juices with higher concentration of starch showed lowervariation in turbidity than the other samples.

The cloud retention in pineapple juice was significantlyimproved by the addition of starch. As studies reported, juicecloudiness occurs mainly due to the suspension of solidparticles [55]. There is a reverse relation between the turbid-ity and amount of sediment in the juice. Consequently, theturbidity decreased as separation of the product increased.In this study, the result showed the starch-added pineapplejuice samples followed this reversible relation. Moreover,the cloud stabilizing effect of starch could be attributed tothe strong water binding characteristics of the starch, whichforms a hydrate shell around the cloud particles that adjuststhe density of the cloud particles with the serum [14].

According to the Stokes law, the larger-sized particles areeasier to precipitate. A good thickener can prevent the forma-tion of large polymers. The difference in absorbance valueswas mainly influenced by the particles that remained insuspension [15, 49].

8 International Journal of Food Science

3.5. Sensory Acceptability of Pineapple Juice. The results ofsensory acceptability of pineapple juices as a function ofstorage time are presented in Figure 1. In this work, theresults for sensory acceptability were presented for the firstday and 7th day of the storage. It can be observed that theeffect of interactions and all main effects was not significanton sensory characteristics of pineapple juice at P ≤ 0:05.The results of sensory testing for taste, flavor, color, consis-tency, aroma, texture, mouth feel, and overall acceptabilityshowed no significant difference (P ≤ 0:05) between thejuices containing potato and anchote starch. Therefore, theaddition of starch did not affect these sensory parameters ofthe pineapple juice. However, pineapple juice with starchaddition showed better acceptability than pineapple juicewith no starch, in terms of appearance, texture, and mouthfeel. As the starch concentration increased in the juice, thepanelists are given sensory score from like very much to likemoderately for all evaluated sensory attributes. The type andamount of starch had no significant effect on sensory accept-ability of pineapple juice. Similar studies have been done byAkkarachaneeyakorn and Tinrat [20] and Lv et al. [15] onthe effect of hydrocolloids on sensory evaluation of mulberryfruit juice and orange juice, respectively. Besides, storage timealso had no significant effect on sensory evaluation of pineap-ple juice even though there was a slight reduction in the sen-sory acceptability scores. The acceptability trend was steadyto some extent with small changes for few sensory attributes.At high concentration of starch addition, the pineapple juicebecomes sticky; therefore, the starch that added to pineapplejuice should keep the original taste of juice.

Subsequently, aroma, flavor, and mouth feel of juice arethe most important factors that affect the pineapple juiceacceptability; all consumers like pineapple juice with goodflavor, mouth feel, and aroma. In terms of the texture, it isalso an important factor; generally, soft texture is easy toaccept by humans. Overall, acceptance of the juices withstarch is important because consumers are not interested inconsuming pineapple juice which is not in good appearance.

3.6. Shelf Life Determination of the Pineapple Juice. The effect ofstorage time, type, and amount of starch on the total viable bac-terial and fungal counts of pineapple juice during storage isillustrated in Figure 2. It can be observed that the effect of inter-actions and main effects was not significant on microbialcounts of pineapple juice at P ≤ 0:05 at the initial day ofstorage. However, a significant effect (P ≤ 0:05) was observeddue to the interactions and main effects after the initialstorage day on microbial counts of pineapple juice. The resultsrevealed that the highest bacterial count was observed in con-trol juice (1:14 × 105 cfu/ml) after 15 days of storage, whereasthe lowest bacterial count (7:04 × 103 cfu/ml) was observed in5% anchote starch-added pineapple juice at the initial day.Besides, the highest fungal count was observed in control juice(1:00 × 105 cfu/ml) samples at the initial day, while the lowestfungal count (8:77 × 103 cfu/ml) was observed in 3% and 5%anchote starch-added pineapple juice after 15 days of storage.In terms of starch type, the highest bacterial count was shownin 1% anchote starch, whereas the lowest is in 5% anchotestarch-incorporated juice. Similarly, the highest and lowestfungal counts were observed in 1% and 5% anchote starch-

0.01.02.03.04.05.06.07.0

Taste

Flavor

Color

Consistency

Aroma

Texture

Mouth feel

Overallacceptability

ControlAS1PS1AS3

PS3AS5PS5

(a)

0.01.02.03.04.05.06.07.0

Taste

Flavor

Color

Consistency

Aroma

Texture

Mouth feel

Overallacceptability

ControlAS1PS1AS3

PS3AS5PS5

(b)

Figure 1: Sensory acceptability of pineapple juice. (a) Initial day. (b) Stored for 7 days. Control: pineapple juice (without starch); AS1: 1%anchote starch; AS3: 3% anchote starch; AS5: 5% anchote starch; PS1: 1% potato starch; PS3: 3% potato starch; PS5: 5% potato starch.

9International Journal of Food Science

added samples, respectively. Juices with anchote starch wereobserved for higher bacterial and fungal counts than juice withpotato starch added. As the starch concentration increased inthe juice, the bacterial and fungal counts decreased significantly(P ≤ 0:05) except between 1% and 3% starch concentrations.Higher bacterial and fungal counts were observed in controlsamples than the starch-added pineapple juice during the stor-age. This can be ascribed to strong water binding characteristicsof the starch, which combine with water to form viscous solu-tions which restrict access of water for microbial growth [46].The pineapple juice with 5% of potato and anchote starch gen-erally showed decreasedmicrobial count than other treatments.

The results revealed that the total bacterial and fungalcount in all pineapple juices increased throughout the storagetime. However, increased starch concentration had a signifi-cant decreasing effect on the microbial content compared withthe control juice during storage. In general, control sampleshowed remarkably high microbial loads during the periodof storage and this may be possibly a major cause of spoilagecommonly experienced by the producers of this product [9].It is evident from this study that the starch-added juicesamples had lower microbial loads when compared with thecontrol juice.

4. Conclusions

The results of this study revealed that addition of potato andanchote starch significantly improved the cloud stability ofthe pineapple juice as compared to the control. The findingsshowed that starch type and starch concentration levels hadsignificantly influenced some of the physicochemical param-eters (turbidity, viscosity, and sedimentation) and microbial

content of the pineapple juice in comparison to the control.Moreover, storage time had significant influenced on turbid-ity, viscosity, sedimentation, and microbial counts of thestored pineapple juice. As starch concentration in the juiceincreased, minimum influence on vitamin C content, TSS,TA, and pH of juice was observed. With increasing in storagetime, turbidity, viscosity, TSS, pH, and vitamin C content ofjuice decreased, whereas sedimentation, TA, and microbialcounts were increased. Adding starch with different concen-trations had not significantly influenced the sensory accept-ability of pineapple juice, even though there were somechanges observed for some sensory attributes. In general, thefindings showed that addition of starch with different concen-trations had significantly influenced some physicochemicaland shelf life of pineapple juice as a function of time.

The result showed that pineapple juice with 5% anchotestarch had better cloud stability during storage period. Thisis because of product exhibited less pulp sedimentation andhigh viscosity and turbidity. Generally, addition of 5% starchhelped in maintaining the cloud stability, reduction in micro-bial load, and no influence on the sensory acceptability of thepineapple juice over a period of 15 days.

Data Availability

The data used to support the findings of this study areincluded within the article.

Conflicts of Interest

None of the authors showed any conflict of interest.

0.00E+00

2.00E+04

4.00E+04

6.00E+04

8.00E+04

1.00E+05

1.20E+05

Cont

rol

AS1

AS3

AS5 PS

1PS

3PS

5Co

ntro

lA

S1A

S3A

S5 PS1

PS3

PS5

Cont

rol

AS1

AS3

AS5 PS

1PS

3PS

5

Initial day 7 15

Pineapple juice stored for 15 daysPCA (B)PDA (M)

Tota

l mic

robi

al co

unt

Figure 2: Microbial load of pineapple juice stored for 15 days. Control: pineapple juice (without starch); AS1: 1% anchote starch; AS3: 3%anchote starch; AS5: 5% anchote starch; PS1: 1% potato starch; PS3: 3% potato starch; PS5: 5% potato starch; PCA (B): total bacterialcount; PDA (M): total fungi count.

10 International Journal of Food Science

Acknowledgments

We express our gratitude to the technical and academic staffof the Laboratory of Food Processing for their pieces ofadvice and support and for providing us with all the neces-sary facilities to carry out this study. Sincere indebtednessalso goes to individuals that have participated in thesensory evaluation of the pineapple juice samples.

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